JPH08306567A - Manufacture of high performance rare earth intermetallic compound magnet by high pressure sintering - Google Patents

Abstract

PURPOSE: To fully show original magnetic characteristics by preparing magnetic powder which is excellent in anti-corrosion by adding a specified dissimilar metal to a rare earth metallic compound or applying it to a surface of the compound and pressurizing and sintering it in a specified intermediate temperature region at a specified pressure. CONSTITUTION: A rare earth intermetallic compound powder which is excellent in anti-corrosion including L2 (Fe, M)17 Nx and Ln2 (Fe, M)17 Cx Nx (Ln:rare earth element) whereto one or more elements of metal M such as CD is added and M'/Ln2 Fe17 Nx and M'/Ln2 Fe17 Cx Nx wherein a metal M' such as Zn is applied to a surface is prepared. This is sintered under a high pressure and a molded item of rare earth intermetallic compound which is difficult to sinter is manufactured. In the process, rare earth intermetallic compound powder such as Ln2 (Fe, M)17 Nx , M'/Ln2 Fe17 Nn is treated at a high pressure higher than 100atm. and at 200 to 800 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing a magnet by sintering a rare earth intermetallic compound having excellent corrosion resistance and magnetic properties under high pressure without using a binder such as a metal or a resin. It is about.

[0002]

2. Description of the Related Art Rare earth intermetallic compound powders that are difficult to sinter and decompose at high temperatures are manufactured by sintering at a temperature lower than the thermal decomposition temperature using a low melting point metal such as zinc or an epoxy resin as a binder. There is.

[0003]

In the conventional method for producing a molded body of a rare earth intermetallic compound which is difficult to sinter, since a large amount of metal, resin, or the like that does not contribute to magnetism is used as a binder, its magnetic performance is originally expected. It was significantly lower than that of the magnetic material, and it was a great obstacle to improving the performance as a magnetic material. Further, by sintering under high pressure, it is possible to obtain a molded product without using a binder that does not contribute to magnetism, but deterioration of magnetic properties due to oxidation cannot be avoided. Therefore, it is necessary to prevent the oxidation and to produce the rare earth intermetallic compound molded body from the raw material powder without oxidizing it so as to exhibit its original magnetic performance.

[0004]

In order to achieve the above-mentioned object, it is essential to develop a manufacturing process of producing a rare earth intermetallic compound powder having excellent corrosion resistance, and heating and sintering the powder without decomposing it. Therefore, in the present invention, a magnetic powder having excellent corrosion resistance is prepared by adding a dissimilar metal to a rare earth intermetallic compound, or by coating the surface of these compounds, and this is subjected to high pressure firing in the medium temperature range from 200 ° C to 800 ° C. It is characterized in that a high-performance rare earth intermetallic compound molded body is produced by bonding.

[0005]

According to the present invention, it is possible to manufacture a rare earth intermetallic compound molded body which is difficult to sinter, without using a binder or the like and without impairing the original excellent magnetic characteristics.

The production is carried out by adding Ln ₂ (Fe, M) ₁₇ N _x and Ln ₂ (Fe, M) ₁₇ C containing one component or more of metal M such as Co.
_{xN y} , and M '/ Ln ₂ F coated on the surface with metal M'such as Zn
This can be performed by sintering a rare earth intermetallic compound powder having good corrosion resistance such as e ₁₇ N _x and M ′ / Ln ₂ Fe ₁₇ C _x N _y under high pressure.

Further, since it is sintered under a high pressure, it becomes a more compact molded body as compared with a conventional rare earth intermetallic compound capable of normal pressure sintering, and accordingly, a magnetic material having higher performance is produced. You can

[0008]

[Example] By the manufacturing process shown in FIG. 1, Ln ₂ (Fe, Co)
It is possible to manufacture a molded body of a hardly-sinterable rare earth intermetallic compound such as ₁₇ N _x , Ln ₂ (Fe, Co) ₁₇ N _x C _y .

The production was carried out by high pressure sintering of the above-mentioned rare earth intermetallic compounds or the metals and compounds constituting them, at a temperature (600 ° C. or lower) at which they do not decompose. As a result, a sintered body of a rare earth intermetallic compound having sufficient mechanical strength and compactness was obtained.

In FIG. 2, Sm₂Fe₁₇N_xPowder and Sm₂(Fe, Co)
₁₇N_xThe powder was subjected to high pressure treatment at 30,000 atm and 600 ° C. for 30 minutes
The powder X-ray diffraction pattern of the sample is shown. Where Sm₂Fe₁₇N
_xWhen powder is treated under high pressure, α-Fe phase is generated by oxidative decomposition.
On the other hand, Sm₂(Fe, Co)₁₇N _xDiffraction pattern in case of powder
No change was observed, and the decomposition reaction into SmN and α-Fe or
Did not proceed with the dissociation of nitrogen.

On the other hand, since the density of the Sm ₂ (Fe, Co) ₁₇ N _x molded body was close to the calculated value (ρ = 7.1 g / cm ³ ), the obtained molded body was sufficiently densified. I found out that

[0012]

According to the present invention, since magnetic powder having excellent corrosion resistance is subjected to high pressure sintering at a relatively low temperature, it is possible to produce a rare earth intermetallic compound molding which is difficult to sinter but has excellent magnetic properties. You can Therefore, a binder such as a metal or a resin that does not contribute to the magnetic properties becomes unnecessary, and the magnetic flux density per unit volume or unit weight increases. Further, by improving the corrosion resistance of the raw material powder, it is effective in producing a high-performance permanent magnet material in which its original magnetic characteristics are sufficiently exhibited.

[Brief description of drawings]

FIG. 1 is a manufacturing process drawing of a rare earth intermetallic compound molded body.

FIG. 2 is a powder X-ray diffraction diagram of the obtained sintered body. However, (a) is a Sm ₂ Fe ₁₇ N _x powder, and (b) is a sample obtained by high-pressure sintering of Sm ₂ (Fe, Co) ₁₇ N _x powder.

Claims (1)

[Claims] 1. Ln₂Fe₁₇N_xAnd Ln₂Fe₁₇C_xN_y(Ln: rare earth
Other metal M as a component to impart corrosion resistance to
Or Ln added more₂(Fe, M)₁₇N_x, Ln ₂(Fe, M)₁₇
C_xN_y(M = Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, A
g, Hf, Ta, W, Re, Os, Ir, Pt, Au) or Ln₂Fe₁₇N_x, Ln₂Fe
₁₇C_xN_y, Ln₂(Fe, M)₁₇N_xAnd Ln₂(Fe, M)₁₇C_xN_yThe surface of
Rare earth intermetallic compound M '/ Ln coated with small amount of dissimilar metal M'₂
Fe₁₇N_x, M '/ Ln₂Fe₁₇C_xN_y, M '/ Ln₂(Fe, M)₁₇N_x, And M '
/ Ln₂(Fe, M)₁₇C_xN_ySingle-domain particle powder of 200 ℃ to 800 ℃
Pressure sintering under high pressure of 100 atm or more in the medium temperature range
Technology for manufacturing high-performance sintered magnets.